1. Field of the Invention
The present invention relates to a vehicle operating system, and more particularly, to means for enabling efficient, stable power feeding for a vehicle regardless of the presence or absence of primarily vertical displacements of the vehicle.
2. Related Art
In the specification, the vehicle operating system means a vehicle, such as a golf cart, an electric car, an electric-powered wheelchair, a truck, an automated guided vehicle and a robot, and a parking facility including means for supplying energy to the vehicle.
Of all the vehicles, a motorized cart has been used as the conventional golf cart. The motorized golf cart, however, has had such problems that noise and exhaust emissions make its performance very bad from the environmental standpoint, and that they are offensive to users.
To solve these problems, JP-A-2000-51419 (prior art 1) discloses a battery-equipped golf cart, for example. The electric golf cart using a battery is environmentally friendly because of no noise and exhaust emissions. The prior art 1 teaches that the battery is contained in the lower part of a front seat, which makes it easy to replace the battery.
Several examples of electric vehicles have also reported in the area of electric cars. In particular, conventional examples of unmanned feeding techniques are described in JP-A-63-87136 (prior art 2) and JP-U-1-79343 (prior art 3).
An automobile charging apparatus of the prior art 2 includes electromagnetic coils provided in a vehicle and on the ground, and means for detecting that both coils face each other in a correct position.
In the prior art 3, grooves for guiding tires of a vehicle are formed on the ground and a vehicle approach detecting switch is so provided that battery charging will start when the vehicle reaches a predetermined position.
In the prior art 1, when the battery goes weak, the battery needs to be manually replaced. Especially, since many golf courses have plural golf carts, battery replacement puts increases loads on workers.
In the case that a golf course is adopting a self-service system in which users or players are required to connect an electric golf cart to the receptacle of a battery charging apparatus after each use instead of battery replacement, the users may find it troublesome to do so, or if a charging station is located in the open air, there is a danger that the users receive an electric shock due to rain or their sweats.
In the case that the electromagnetic coils or transformers are placed in the vehicle and on the ground as disclosed in the prior art 2, a magnetic flux transmitted between the coils develops in the vertical direction. In such a form of noncontact power feeding, charging characteristics largely vary depending on the width of a gap between the coils. In other words, the larger the width of the gap, the smaller the excitation inductance between the coils, which results in an increase in leakage inductance. On the other hand, the smaller the width of the gap, the larger the excitation inductance between the coils, which results in a decrease in leakage inductance.
Variations in excitation inductance between the coils may bring about fears of adverse effects such as frequency fluctuations in charging current. If the frequency is too low, the transformers may cause magnetic saturation, while if the frequency is too high, sufficient control of the charger may be impossible.
In the case that a magnetic flux transmitted develops in the vertical direction as in the prior art 2, the gap width changes according to the tire pressure or the weight of baggage loaded on the vehicle, which makes it difficult to recharge the vehicle stably.
It is considered possible that both coils are brought into contact with each other to prevent the occurrence of a gap. Bringing the coils into contact with each other, however, may cause a short circuit or break due to wear by friction or corrosion and therefore require frequent maintenance of the coils.
In the prior art 2, when the vehicle is to be stopped at a predetermined position, the front and rear of the vehicle can be positioned by using a car stop. On the other hand, it is very hard to position the right and left of the vehicle. As a result, positioning of the vehicle has to be repeated until the vehicle is parked in the predetermined position.
In the prior art 3, the grooves for guiding the tires need to be formed on the ground. Therefore, like the golf carts, if one golf course has plural vehicles, a plurality of grooves need to be newly formed, which requires time and costs for the installation or construction.
Further, in the prior art 3, although the right and left of the vehicle can be positioned, it is very hard to position the front and rear of the vehicle.
It is an object of the present invention to provide a vehicle operating system constituted of a vehicle and at least a charging apparatus, the system comprising means for enabling high-precision unmanned positioning despite primarily vertical displacements of the vehicle due to changes in tire pressure and the like, and hence enabling high-efficient, stable power feeding.
To attain the above object, and according to the present invention, there is provided a vehicle operating system constituted of a parking facility including at least a charging apparatus, and a vehicle possibly displaced primarily in the vertical direction, the vehicle operating system comprising a power feeding unit connected to the charging apparatus and a power receiving unit mounted in the vehicle, in which when the vehicle is stopped at a predetermined position in the parking facility, the power feeding unit and the power receiving unit face each other in a correct position so that a magnetic flux for feeding power by magnetic coupling will develop substantially in the horizontal direction.
The vehicle has tires and/or a suspension system modifiable according to the load.
There are two cases where the power feeding unit has a C-shaped transformer and the power receiving unit has an I-shaped transformer, and where the power feeding unit has an I-shaped transformer and the power receiving unit has a C-shaped transformer.
When the power feeding unit and the power receiving unit face each other in a correct position, the I-shaped transformer is positioned in a gap of the C-shaped transformer.
In either case, when tire guides for guiding the vehicle to a power feeding position and a car stop are provided, the width between the tire guides becomes substantially equal to the tire width, and the car stop is so located that when the vehicle comes in contact with the car stop, the power receiving unit and the power feeding unit will face each other in a correct position.
The vehicle operating system may further comprise a detection device for detecting that the vehicle has come in contact with the car stop and making the power feeding unit start charging.
The width of a gap between the power receiving unit and the power feeding unit is set larger than the width of the tire guides and the tire.
Another configuration is possible in which a pair of tire guides has such a length that a plurality of vehicles can be placed thereon at the same time, and a plurality of power feeding units are provided along the pair of tire guides substantially at such regular intervals that intervehicular contact will never happen.
The vehicle operating means may also comprise communication means for guiding each vehicle to a rechargeable position.
The vehicle may further comprise a mechanism for making part of the power receiving unit project outside of the vehicle in synchronization with a braking mechanism of the vehicle.
According to the present invention, the charging apparatus includes the power feeding unit and the vehicle includes the power receiving unit, so that power is fed in a noncontact manner, thereby charging the vehicle without manual assistance.
Further, since the use of a combination of the C-shaped and I-shaped transformers for the power feeding unit and the power receiving unit enables the magnetic flux to develop substantially in the horizontal direction, high-efficient, stable power feeding becomes possible despite primarily vertical displacements of the vehicle due to changes in tire pressure and the like.
Furthermore, since the tire guides for guiding the vehicle to a charging position and the car stop are so used that when the vehicle comes in contact with the car stop, the power receiving unit and the power feeding unit will face each other in a correct position, high-precision positioning can be realized at power feeding time.
Other objects, features and advantages of the invention will become apparent from the following description of the embodiments of the invention taken in conjunction with the accompanying drawings.